


Legs

by Dalektable (orphan_account)



Category: Supernatural
Genre: Alternate Universe, Alternate Universe - The Little Mermaid, Angst, Arranged Marriage, F/M, M/M, Merman Castiel, Merman Gabriel, Mershark Crowley, Mute Castiel, Not Beta Read, Political Marriage, Prince Castiel, Prince Dean Winchester, Prince Sam Winchester
Language: English
Status: In-Progress
Published: 2014-03-05
Updated: 2014-03-31
Packaged: 2018-01-14 16:01:22
Rating: Teen And Up Audiences
Warnings: Major Character Death
Chapters: 2
Words: 4,300
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1272619
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/Dalektable
Summary: <blockquote class="userstuff">
              <p>It's not that Castiel wants to leave the sea, it's just that he wants so much more.</p>
            </blockquote>





	1. Of Storms and Saviors

**Author's Note:**

> This is not based on the Disney's The Little Mermaid, but instead, the Hans Christian Anderson original story. I'm still adding my own twists on it, but there will not be a happy ending. Not beta read, but run through Hemingway and edited multiple times by myself.

Castiel pushed his head above the crashing waves, holding the rotting wood of the pier to keep himself steady. It was around this time of day that Dean usually showed up at the beach, often with his younger brother, and sometimes with women. It was almost never the same woman. Lately, though, it had been the same woman with dark, wild curls for hair and a princess' grace to her step. Castiel had heard Dean call her "Cassie" and he wasn't sure he liked her recurring appearances on his beach. Today, Dean showed up with her again, and Castiel couldn't help but stare. They held hands as they walked along the rocky shore, talking.

Castiel frowned, watching them from the water. He liked it better when Dean was alone, or with Sam. That way he could pretend that Dean wasn't the womanizer he appeared to be. When he was with giggling women, that side of Dean came out. It gave Castiel no choice but to look at it. That persona felt strange to Castiel, who was so sure he knew the _real_ Dean Winchester. 

Although they meant their conversation to be private, Castiel listened to him tell her about the long trip he was going to be taking to a neighboring kingdom. His father wasn't going to be able to make it, and they needed to establish rules. Their conversation faded into the distance of Castiel's mind as he watched their forms. He focused on Dean's strong legs working beneath the strange material that covered them. Or on Cassie's slender ones making a vague impression against her own swath of material with every step. If only Castiel had legs. Then he might be able to walk with them.

His grip tightened on the support of the pier. Gabriel told him that his crush on the human prince was silly and would never come to anything. And although Castiel knew that they were from different worlds, he couldn't help but hope for something beyond his reach. He gave the two on the beach a longing glance, deciding to give them some privacy.

He ducked back under the sea, pushing himself through the water, deeper and deeper, brushing aside dancing seaweed and schools of small fish. The city of Atlantis loomed in front of him within a short swim, and he prepared himself to go home. It wasn't that he hated home, but it certainly wasn't the best of places. Atlantis was a combination of monarchy and a militant state. It was the only official city in the ocean; you either lived in Atlantis or you were a poor, homeless, drifter. And being son of the king, Castiel had never had a choice.

He looked both ways before swimming into the castle and into his room, shutting the door behind himself in a flurry of bubbles. He felt grateful that no one had caught him sneaking out. Or sneaking back in. He'd only just settled himself on his bed of kelp when Gabriel came into the room. He shut the door far louder than Castiel ever would have.

"Cassie!" he said between his teeth, the words coming out in a sharp hiss. "I had to cover for you again." Castiel knew that his habit had to be getting quite out of hand if it was annoying even Gabriel.

"I am sorry, brother," he said, cocking his head to the side.

"Yeah, I know, but you still need to stop staring like a creeper at that human. I can't continue to explain your absences to Father."

Castiel nodded, flipping the end of his tail indignantly. Their father, head of this militant state, was even worse on his children than he was on their soldiers.

"By the way," Gabriel said, already turning to leave. "You were practicing for the concert next week. It was a hard stretch to get him to believe, but it worked out." It was amazing that they had any time to themselves, because their father made them work endlessly. Castiel supposed he could understand, he wanted them to be good royals, but why Cas? He was the youngest in a line too long for him to ever take the throne. What good would it do to force singing and history and music and literature on Castiel?

All if the brothers had their faults and their successes. It was often said that Michael was too cold hearted, but he knew the history and how to rule the land as well as their father. Gabriel was too distracted, but he could come up with elaborate plans.

Castiel was a dreamer, but other merfolk admired his voice. It crackled like the lightning he sometimes heard above water, and rumbled like the thunder that followed. It was a rough sound, but a pleasing one. His brothers often told him that he could have his pick of the merfolk in the city, but it didn't seem that Castiel wanted another merperson.

He sighed and laid back on his bed. Gabriel gave him another look and then left him alone. He stayed there, the kelp and his thoughts weaving in the seawater around him. He hadn't seen Dean with the same woman more than once before, and although he had no claim over the man, Castiel felt jealous of Cassie.

He and his six brothers were only allowed one trip to the surface, and it was on their fifteenth birthday. Castiel had been making trips to the top since he was thirteen, and even now, in his early twenties, he was still doing it. If the king knew, he'd be angry. And so far, he'd managed to keep it a secret, and he intended to keep it that way.

But he didn't know what to do. After all this time, he felt like he knew Dean. He'd heard the man speaking to his younger brother often enough to know a lot about him. And he had heard a lot that he'd said with his various women. Even so, Dean didn't know him. If he did, Castiel knew that if the fish tail wasn't enough to turn Dean away, his flat chest and deep voice would be.

He gripped the kelp in frustration and got up, swimming to the other side of the small room, looking out the window onto the rest of the city. From there, he could see the outskirts, the shadowy parts just outside the boundaries. Castiel knew the stories about the merfolk who lived there, stories of dark magic and deals gone wrong. The thought intrigued him, but he was so overprotected it was amazing he managed to sneak out as often as he did.

He sighed, swimming away from the window and settling at his desk. As often as he was shirking his duties, he was working hard to please his father. He at least had to appear to be a good son. He studied the history of Atlantis until he fell asleep.

He woke up with his head crooked on the desk and a kink in his neck. Castiel winced and tried to stretch it, encountering searing pain that ended that endeavor. He looked out the window and saw that the sun wasn't too high yet. He had enough time to go out and get back in the castle before his father noticed. He slung his bag over his shoulder, and swam out the window as an extra measure to keep this venture secret. If he was careful, no one would have to cover for him today.

He swam for a while until he got to the ship bay, where he could see a swarm of official-looking people gathered around the largest ship. Dean would be taking off on that particular boat today, to go on his diplomatic mission. He pulled himself up on a rock, watching from far enough that people shouldn't spot him. And if they did, they wouldn't be able to see his tail.

His dark hair plastered to his forehead, but he knew from experience that it would dry sticking up in all directions. He liked it that way, even if it had considerably less motion than it did when it moved with the water. His tail was a dark blue, almost teal in color. He kept it tucked underneath himself, in the water so that it wouldn't become too dry. That was also something he'd learned from experience. He had to occasionally dip below the surface to wet the dorsal fin on his back as well.

He was just in time to see the boat take off, but Castiel worried about this journey. He could see the far off darkening of the sky and he knew that that meant by now for the ocean. Those were the times when the waves crashed highest on the sides of ships and washed over the beaches, a destructive power as frightening as it was beautiful.

Concerned, he followed the ship's wake, keeping close. The water became more wild the longer he swam, and the sky darkened. Castiel lost track of how long he'd been gone, but he knew by now that his father was going to catch him. It didn't matter. He had a bad feeling about this ship and about this storm that was pulling its way in.

It felt like the thickest clouds rolled in all at once. Lightning lit through the sky, mesmerizing Castiel. He rarely had the chance to look at this phenomenon. But he also knew that the lightning meant danger, at least to ships in the water. The waves were crashing into his face; he was having a hard time figuring out whether to use his gills or his lungs to breathe from one moment to the next. The boat was rocking dangerously, and Castiel found himself moving back out of its range.

He hoped that Dean would be safe, but he was here to protect him in case he wasn't. Castiel scanned the figures on the ship, looking for his prince. He found that he couldn't distinguish one figure from the next. On top of that, the waves were reaching even higher, splashing on the deck. He could hear people screaming orders at one another. They were trying to salvage a trip that they should have never made.

Castiel couldn't see anything but open water around him. The only thing he had to latch onto was the ship, and just like that, it was falling apart. Now the screams were in fear. He could see people falling from the deck into the waters below. Castiel swam to save them, but they all found pieces of the ship to hold onto. Most of the people were choking back water, but at least they were alive.

And then Castiel saw him: Dean. He was paddling, trying to fight against the waves. They were pushing against him, unending. It was a losing battle for someone who wasn't meant to live in water. But Castiel was born to live here, and he could do something about it.

Without much of a thought to the other people on the ship, he hoisted Dean onto his back and started swimming in the direction he'd come from. He took dips under the water when he was sure Dean wasn't inhaling, trying to go as fast as possible. When he thought he was going to give up from exhaustion, he forced himself to keep swimming.

By the time he reached the beach, he felt like his tail was going to fall off, but the sun was out and they were safe. He laid Dean out on the sand, hauling himself up after him to make sure he was breathing. The grit and grain of the sand felt good against his skin, and for a moment, he just reveled in the closeness he knew they would never have again.

He lay there in the sun, next to Dean, for a few moments, and then his prince began to stir. Castiel hastily pressed a kiss to his forehead and another to his cheek, then dove back into the water, swimming far away to watch. Dean woke on the beach, alone and confused. But Castiel could not go to him. Not without revealing what he was. Instead, he just swam away, leaving the prince behind him.


	2. Of Legs and Contracts

**Summary for the Chapter:**

> Castiel makes a deal, and Crowley doesn't seem to get anything.

**Notes for the Chapter:**

> Changed certain details for the sake of a little humor in the next chapter. And Crowley's not out of the game just yet.

It was a short swim to the palace in Atlantis, but between the apprehension and the soreness of his tail and arms, it felt like forever. But even forever had to end, and he was in front of his home, looking up at its gleaming towers in awe that never faded. He hesitated for a moment before swimming in through the palace entrance. For a moment, he thought he was free, but then he saw Joshua, his father's right-hand man. He flared his gills in anticipation, and then swam towards him, as ready as he ever would be.

The worst thing about Joshua's reprimands was how calm he was. He was waiting for Castiel with a steel look in his eyes, but everything else about him seemed unaffected. Castiel came to a stop in front of him, looking straight ahead.

"Where have you been?" Joshua asked him. "You completely missed your history lesson and music practice." Castiel knew he couldn't tell the truth, and scrambled to come up with a lie.

"I was exploring the caves outside of the city," he said, keeping his voice strong as he said it. Joshua was excellent at detecting lies. But if he knew anything, he didn't let it show.

"There was a storm on the surface today," Joshua said. "We were worried about you." Even the worst storms could make the water dangerous if the merfolk swam too close to the surface. And although most people didn't know that he went _above_ the water, they did know that he had a habit of swimming in the danger zone. Castiel brushed off the comment. The "we" never seemed to include his father unless the "we" was angry with him for something. 

"I'm fine, thank you, Joshua." Castiel turned to swim away, hoping that this short conversation might be all, but Joshua stopped him with a hand on the arm. He gestured towards the throne room.

"The king wishes to speak with you," he said. Castiel's gill flared again, and he swallowed a lump in his throat.

"Right," Castiel said, giving Joshua a nod and swimming towards the throne room. There weren't doors that closed, as a symbol of the king's openness to speak with his subjects. It was a large arch, instead, that differentiated. It was decorated with jewels and ornaments from all over the ocean, which gleamed in the light provided by glowing orbs. The king hired a magician to do all the lighting for the city. From what Castiel understood, it took a lot of power, and a lot of homes were often left dark. They didn't get much sunlight from the surface, not when they got this far down. That was why Castiel liked his room so much; it was in one of the highest towers, tall enough that he could see some natural sunlight.

As he swam through the arch, two guards moved their spears out of the way. Despite the apparent openness of the palace, it was heavily guarded. In his early years of sneaking out, Castiel had made it a game to see how many guards he could pass without being spotted. Now it was just a chore.

The massive, golden throne rose above him, and he could see his father sitting right in the middle. The seat could easily hold a man three times the size of the king, and it, too, shone in the mystical light of the orbs. Castiel couldn't see the look on the king's face from where he was, but he knew that it looked like. The corners of his mouth turned down, just enough too look a little grumpy, like someone had dropped his morning kelp on the ground. It was all the emotion he would allow on his face. Kings had to be strong, after all. Kings were merely soldiers.

He stopped a few feet from the base of the throne, feeling dwarfed by its size. His father wouldn't come down from the throne. He'd scold Castiel like a king ruling subjects. He couldn't remember the last time the king had actually treated him like a son rather than a robot.

Castiel flipped his tail nervously, staring up, up, up at the king. Unlike Castiel's dark blue scales and light blue fins, the king had orange. The fin on his back and the fins on his hips had lighter, almost yellow, skin stretched between spines. He kept his trident, the sign of his status, on him at all times. The threat of roaming merpeople was constant.

"You've been skipping a lot of lessons lately, Castiel," he said, voice booming.

"I know," Castiel said. The king's tail flopped into the throne with a loud thud.

"And you need to work on better attendance. I won't have my sons running about like  _street urchins._ " 

"I know."

"You can't just spend all your time watching the kelp grow and...what were you doing today?" The king leaned forward in his seat as if anxious to see what Castiel had to say.

"I was exploring the caves outside of Atlantis," he said. The king's face turned red.

"Outside of the city?" he asked, voice deceptively calm.

"Yes," Castiel answered. It was always best not to argue with the king, but to just let things be and go along with it. Soon enough he'd been in his room, no worse for the wear.

" _Outside of Atlantis,_ Castiel, you  _know_ what I've taught you about going out of the city boundaries. You have to have more common sense, you're a  _prince_ , act like it for once in your life." The king's voice was growing louder. 

"You could have been  _killed._ Rogue mersharks live out there, and thieves and murderers, and do you know what they could get for the tail of a prince?" 

The king was always hysterical about the princes leaving city boundaries. Only Michael was permitted to leave, and only with a group of guards that would give their lives for him. Castiel thought that he hadn't always been this way, and only became so attuned to the danger after his wife was murdered and her dead body strung up on the outside of the castle. He'd immediately shut down any sense of freedom that his sons had when he'd learned of her, immediately following the week long, traditional mourning period.

"I understand," was all Castiel said. The king put his head in his hands and his gills flared.

"Okay, Castiel. Go to your room, prepare for double history and music lessons tomorrow."

Castiel swam away feeling somewhat triumphant that all he had to double up on was music and history. There wasn't too much to Atlantean history, given that they were usually peaceful, with only the occasional raid or battle with organized groups of rogues. Anything peaceful wasn't typically written down, outside of law reforms. It wasn't the most interesting, but at least it wasn't hard.

He swam up to his room, settling down on his bed, thinking about Dean. He'd finally gotten to see him up close. There were so many things that Castiel had been able to see about him from that close that he hadn't from a distance. For one, his eyes were greener than kelp, from what he'd seen before the prince had passed out, and his nose was generously gifted with freckles. They spread onto his cheeks and neck, too, from what Castiel could see. He thought they were beautiful.

And Castiel had been able to tell before that he was fit, but carrying him to shore, he'd felt it. Dean did a lot of physical exercise, that much was obvious. He'd never felt another person's torso underneath his fingertips before, man or woman, and he decided that he very much liked the feel of it. Dean's chest was strong and study, the way a good prince should be.

And there was Gabriel, opening the door without regard for privacy. Castiel sighed in the way that merpeople did, with a flare of the gills, and lowered his head into his hands.

“What do you want?” he mumbled.

“I head you got a verbal beating from Daddy Dearest.” Gabriel was leaning against the closed door, some sort of sweet popped in his mouth.

“It wasn't bad,” he said, finally raising his head to look at Gabriel.

“You always say that,” Gabriel replied, crossing the room and settling himself down on Castiel's bed.

“He didn't say anything I didn't expect him to say.”

“He never does,” Gabriel was lounging back now, taking up more room than Castiel was, although he was smaller.

“We never learn about humans,” Castiel said, looking over at Gabriel.

“No,” he replied. “Why are you bringing this up?”

“You always know more. You have ways of getting information Father doesn't want us to know. What have you heard about humans?” Castiel looked at him with big, blue, pleading eyes. Gabriel swallowed. There was a period of time where he learned anything he could about people above the water, but he had never thought to share any of it.

“They have this thing called fire,” Gabriel began. “It gives them light the way we get light from magic. And they have towns and cities all over the land, everywhere. And when they swim, they flail all of their limbs around like they're dying. They have souls, which they believe live on beyond them into death which is--”

“Souls?” Castiel asked.

“Some incorporeal thing that encompasses everything they are, or something like that.”

“And we don't have souls?” They didn't have lore like that, at least. Everyone knew that when you died, you were just gone. Merpeople lived longer than humans, but they all died eventually.

“They don't exist, Castiel,” Gabriel said, giving him an odd look.

“Of course,” Cas said, straightening up. “I think I want you to leave, now, please.” Gabriel looked at him with eyebrows raised higher, but complied, swimming out of the room with one last “Anything you need, baby bro.”

Castiel watched the door after he was gone, just to make sure he wasn't coming back, and then swam out the window again. It was more dangerous to swim later into the day, particularly where he was going, but there was something he needed to do.

He wanted to be part of the human society, at least for a while. If it wasn't forever, that was okay, because he did have a life under the sea. There was a part, just outside of Atlantis, that he knew of, just from hearsay, but it was worth the chance. Crowley was an infamous mershark with magic of the old sort long lost to most merfolk. He asked steep prices, but Castiel was sure he could manage the price.

He swam in the dark sea for a while, still worn out from the day but filled with a sense of importance. He got to the caves he'd spoken of before, looking for the one Crowley was said to hide in. A faint light was emitting out of one, and Castiel pushed himself faster to the cave's entrance. It was almost empty, but he saw floating orbs of a lightly more orange shade than the ones around the city. With only slight hesitation, Castiel swam further into the cave.

“What would a prince be doing in my humble shop?” A voice called out from the shadowed areas towards the back. Castiel jumped, and then stopped. He looked around for the source of the low, smarmy drawl.

“Crowley?” he asked.

“That would be me,” the man said, swimming out from the corner. As with all mersharks, his lower half was more aligned with a shark than any other fish. His scales were dark grey, with a white underbelly, and he had fins on his forearms and gills on his neck, tinged grey like his lower half. But other than that, he appeared to be a middle-aged merman, which meant he could be anywhere from 200 to 400 years old. Castiel moved back as Crowley approached.

“And what can I do for you that your father can't buy you?”

“I want a soul,” Castiel said. “I want to be human.”

“And what will you give me in return?” Crowley asked, swimming in circles around Castiel. Castiel held his ground, back straight, head up like a good prince. Castiel opened his mouth to answer when Crowley began speaking again.

“Since I'm such a nice guy, I'll give this one to you for free.” The grin that spread across his face wasn't quite kind, but Castiel ignored it in favor of listening. “With a few stipulations of course. Are you still willing to proceed?”

“Yes,” Castiel said without a moment's hesitation.

“Excellent,” Crowley said, swimming over to rummage around in the corner. He came back out with a rolled up piece of parchment. The mershark gave him a wide grin and then let it unroll. “There are just a few things we need to go over.”

Castiel nodded.

They spoke for a while, going over the contract, in detail, as Castiel had wanted, but the main point was simple. If Castiel was not married to someone he was in love with after three months, he would die. He thought of Dean and knew that he could manage it. And without a second thought, Castiel signed on the dotted line, name shining before it settled into the paper. Crowley grinned like he'd just won first prize at the county fair.


End file.
